Asus X800XT PCX Video Card Review :: Features

11-29-2004 · Category: Hardware - Video Cards

By Benjamin Sun
  • DirectX 9.0c support
  • OpenGL 1.5 support
  • Pixel Shader 2.0b
  • Vertex Shader 2.0
  • 3Dc
  • SmoothVision HD

The Asus eXtreme AX X800XT supports the latest and greatest APIs (Application Programming Interface) DirectX 9.0c and OpenGL 1.5. It's important to note that most game developers are targeting DirectX 9.0 for games like Half Life 2 and Stalker. Valve Software says that the fastest ATI card is faster by 20-30% over the fastest equivalent NVIDIA card. We'll have to see about that J.

DirectX 9.0c is Microsoft's latest API. Microsoft releases a new API every year or two adding new features that new graphics cards support. DirectX 6.0 introduced EMBM (Environmental Mapped Bump Mapping) and multi texture support, DirectX 7.0 brought support for Hardware Transform and Lighting. DirectX 8.0 introduced Pixel Shaders and Vertex Shaders to the API. 2002 saw the release of DirectX 9.0 which included Pixel Shader 2.0 and Vertex Shader 2.0 as the major new features. The RADEON 9700 Pro was the first video chip to fully support DirectX 9.0 Pixel Shader 2.0 and Vertex Shader 2.0.

The X800XT supports Pixel Shader Model 2.0b. Whereas the 9700 Pro supports Pixel Shader 2.0 and 160 PS instructions in a single pass, the X800XT supports 512 Texture, 512 Vector and 512 Scalar instructions in a single pass. This gives a total of 1536 PS instructions in a pass. More instructions can be done with multi-passing.

Vertex Shader Model 2.0 supports 65080 instructions in a single pass with loops and branches. The X800XT has 6 vertex shader units, giving a maximum theoretical of 1.5 triangles per second throughput an increase from the 1 per second of the 9800XT series. One feature that the R3xx and R4xx series doesn't support is vertex texturing so it's short of the Vertex Shader 3 model.

3Dc is ATI's trademark for normal map compression. A normal map can fool the eye into seeing more geometric detail than is actually present by using shadows and 3 vectors of information, X-axis, Y-axis and Z-axis. This differs from a bump map which only has one plane of information, a height map. When compared to a normal map, a bump map looks flattened and not as rich as the normal map.

SmoothVision HD is ATI's trademark for their image quality improving features, specifically Anti Aliasing and Anisotropic Filtering. Antialiasing helps get rid of jaggies in games and applications. ATI uses a semi-scattered pattern of AA that is generally thought of as superior to NVIDIA's implementation. The R3xx and higher chips also support gamma correction in anti aliasing allowing for better colors in the games. The X800XT supports up to 6 samples AA. Recently ATI introduced something called Temporal Anti-Aliasing, which can provide a superior image quality. Anisotropic Filtering can sharpen textures in games. In this instance, it's generally held that NVIDIA's implementation is slightly better than ATI's.